Name: TMS: Using the Theta-Burst Protocol to Explore Mechanism of Plasticity in Individuals with Fragile X Syndrome and Autism (Video) | JoVE Journal
Uploaded: 2010-12-28T17:30:00.000+00:00
Duration: 10 min 58 s
Description: Explore theta-burst TMS to study cortical motor plasticity in Fragile X Syndrome and autism. This protocol measures motor-evoked potentials to reveal neurophysiological differences in neurodevelopmental disorders.

ai_agent_IP

ai_agent

maintenance

instantTrialDurationMinutes

isBiopharma

enableNewMyJoveSectionDesign

educationFeatures

seoMetaApi

ai_copilot_institution_blacklist

ai_chat_institution_blacklist

freeAccessWindow

ssoRoleCapture

scheduledMaintenanceBanner

joveLabsFeatures

disable_autoplay_for_bots

extended_trial_duration

5 minutes

1. Determine Resting Motor Threshold:
<ol class="lalpha">
 <li>To begin, seat your subject in a comfortable chair.</li>
 <li>Next, apply EMG surface electrodes over the first dorsal inerosseus muscle of the subject's right hand. (INSERT FIGURE1) If you are having trouble locating this muscle, ask the subject to make a pinching motion or to move his/her index finger back and forth - this should make the muscle easier to locate.</li>
 <li>Place a ground electrode on the meaty portion of the subject's forearm.</li>
 <li>Determine the location of the subject's left motor cortex. Although this area differs slightly for everyone, it will generally be around 3.5 cm rostrolateral of cranial vertex. Do not be afraid to explore a small grid around this region and adjust the angle of stimulation until finding the motor "hotspot".</li>
 <li>Once you've found M1, starting at 50% power, begin single pulse stimulation to this region and measure the resultant evoked MEPs.</li>
 <li>Adjust the power up or down until you are able to produce an MEP of greater than 50 μV on exactly 5 out of 10 consecutive pulses. This power level is the subject's resting motor threshold.</li>
</ol>
2. Determine Active Motor Threshold
<ol class="lalpha">
 <li>Using the same electrode set-up as described above, ask the subject to pinch his/her right forefinger and thumb together using about 20% pressure.</li>
 <li>While the subject holds this pinching position, begin single-pulse stimulation at 50% power over M1 and measure the resultant MEPs.</li>
 <li>Adjust the power up or down until you are able to produce an MEP of greater than 200 μV on exactly 5 out of 10 consecutive pulses. This power level is the subject's active motor threshold.</li>
</ol>
3. Determine Baseline Mep
<ol class="lalpha">
 <li>To determine a subject's baseline MEP amplitude, stimulate motor hotspot at 120% resting motor threshold with 10 single pulses.</li>
 <li>Measure the MEP after each pulse.</li>
 <li>Average the MEP values from three batches of 10 pulses.</li>
</ol>
4. Setting TMS Parameters
<ol class="lalpha">
 <li>We will be utilizing standard Theta-Burst parameters: three pulses at 50 Hz at an intensity of 80% active motor threshold for 200 ms intervals.</li>
 <li>To administer intermittent TBS, generate a two-second stim train (at the aforementioned parameters) followed by eight-seconds of no stimulation. Repeat for 190 seconds (a total of 600 pulses). iTBS has been shown to facilitate cortical activity.</li>
 <li>To administer continuous Theta-Burst, generate an uninterrupted stim train (at the aforementioned parameters) for 47 seconds (a total of 600 pulses). cTBS has been shown to inhibit cortical activity.</li>
</ol>
5. Tms Stimulation
<ol class="lalpha">
 <li>For this protocol, administer either iTBS or cTBS over the earlier established M1 motor hotspot.</li>
</ol>
6. Determine Post-stimulation MEP
<ol class="lalpha">
 <li>Following TBS, as before, stimulate motor hotspot at 120% resting motor threshold with 10 single-pulses.</li>
 <li>Average the batch of 10 MEP levels.</li>
 <li>Collect new 10-pulse batch averages at 5 minutes, 10 minutes, 20, 30, 40, 50, 60, 75, 90, 105, and 120 minutes post-stimulation.</li>
</ol>
7. Representative Results
When utilizing an iTBS pattern, you should notice an increase in MEP values for a duration reflecting the subject's natural state of plasticity. Likewise, when utilizing a cTBS pattern, you should notice a decrease in MEP values for a duration reflecting the subject's natural state of plasticity.
<img src="/files/ftp_upload/2272/2272fig1.jpg" alt="Electromyography (EMG) test diagram, head and hand setup, muscle signal recording process." data-altupdatedat="1788235205000" data-alt="Figure 1"> Figure 1. Diagram of electrode placement for MEP measurement.
<img src="/files/ftp_upload/2272/2272fig2.jpg" alt="Corticospinal excitability process, cTBS/iTBS diagram, MEP amplitude graph, LTP/LTD plasticity." data-altupdatedat="1788235205000" data-alt="Figure 2"> Figure 2. Diagram of the iTBS stimulation pattern.
<img src="/files/ftp_upload/2272/2272fig3.jpg" alt="cTBS diagram with 3-pulse burst at 50 Hz for neural stimulation analysis." data-altupdatedat="1788235205000" data-alt="Figure 3"> Figure 3. Diagram of the cTBS stimulation pattern.

<ol><li>Pfeiffer, B. E., Huber, K. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((The+state+of+synapses+in+fragile+x+syndrome%5BTitle%5D)+AND+%22Neuroscientist%22%5BJournal%5D)">The state of synapses in fragile x syndrome.</a> Neuroscientist. 15, 549-567 (2009).</li>
<li>O'Donnel, W. T., Warren, S. T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((A+decade+of+molecular+studies+of+fragile+x+syndrome%5BTitle%5D)+AND+%22Annual+Review+of+Neuroscience%22%5BJournal%5D)">A decade of molecular studies of fragile x syndrome.</a> Annual Review of Neuroscience. 25, 315-338 (2002).</li>
<li>Tassone, F., Hagerman, R. J., Taylor, A. K., Mills, J. B., Wood, S., Gane, L. W., Hagerman, P. J. American Journal of Human Genetics. 65, A493-A493 (1999).</li>
<li>Hagerman, R. J., Miller, L. J., McGrath-Clarke, J., Riley, K., Goldson, E., Harris, S. W., Simon, J., Church, K., Bonnell, J., Ognibene, T. C., McIntosh, D. N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Influence+of+stimulants+on+electrodermal+studies+in+fragile+x+syndrome%5BTitle%5D)+AND+%22Microscopy+Research+and+Technique%22%5BJournal%5D)">Influence of stimulants on electrodermal studies in fragile x syndrome.</a> Microscopy Research and Technique. 57, 168-173 (2002).</li>
<li>Miller, L. J., McIntosh, D. N., McGrath, J., Shyu, V., Lampe, M., Taylor, A. K., Tassone, F., Neitzel, K., Stackhouse, T., Hagerman, R. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Electrodermal+response+to+sensory+stimuli+in+individuals+with+fragile+x+syndrome%3A+a+preliminary+report%5BTitle%5D)+AND+%22American+Journal+of+Medical+Genetics%22%5BJournal%5D)">Electrodermal response to sensory stimuli in individuals with fragile x syndrome: a preliminary report.</a> American Journal of Medical Genetics. 83, 268-279 (1999).</li>
<li>Hagerman, R. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Fragile+X%3A+perspectives+from+birth+through+aging%5BTitle%5D)+AND+%22Biological+Psychiatry%22%5BJournal%5D)">Fragile X: perspectives from birth through aging.</a> Biological Psychiatry. 57, 73s-73s (2005).</li>
<li><a target="_blank" href="http://scholar.google.com/scholar?hl=en&safe=off&q=%22Handbook+of+Transcranial+Magnetic+Stimulation%22">Handbook of Transcranial Magnetic Stimulation</a>. Pascual-Leone, A., Davey, M., Wassermann, E. M., Rothwell, J., Puri, B. , Edward Arnold. London. (2002).</li>
<li>Walsh, V., Pascual-Leone, A. <a target="_blank" href="http://scholar.google.com/scholar?hl=en&safe=off&q=author%3aWalsh%2C+V+%22Transcranial+Magnetic+Stimulation%3A+A+Neurochronometrics+of+Mind%22">Transcranial Magnetic Stimulation: A Neurochronometrics of Mind</a>. , MIT Press. Cambridge. (2005).</li>
<li>Thickbroom, G. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Transcranial+magnetic+stimulation+and+synaptic+plasticity%3A+experimental+framework+and+human+models%5BTitle%5D)+AND+%22Experimental+Brain+Research%22%5BJournal%5D)">Transcranial magnetic stimulation and synaptic plasticity: experimental framework and human models.</a> Experimental Brain Research. 180, 583-593 (2007).</li>
<li>Huang, Y. Z., Edwards, M. J., Rounis, E., Bhatia, K. P., Rothwell, J. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Theta+burst+stimulation+of+the+human+motor+cortex%5BTitle%5D)+AND+%22Neuron%22%5BJournal%5D)">Theta burst stimulation of the human motor cortex.</a> Neuron. 45, 201-206 (2005).</li>
<li>Oberman, L., Eldaief, M. C., Gautam, S., Fecteau, S., Tormos, J. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Abnormal+Cortical+Plasticity+in+Adults+with+Asperger%27s+Syndrome%5BTitle%5D)+AND+%22%22%5BJournal%5D)">Abnormal Cortical Plasticity in Adults with Asperger's Syndrome.</a> , Forthcoming Forthcoming.</li>
</ol>

No conflicts of interest declared.

Knowing that prolonged duration of TMS after-effects is reflective of atypical neural plasticity, studies such as this could serve to create better and more precise diagnostic protocols for Autism and related disorders.
Similarly, with more data, we may be able to find temporal biological markers for other neurological pathologies - including Fragile X syndrome. In this case, although there is not yet a therapeutic remediation option, early detection could help parents and educators determin...

<table><tbody><tr><td>Alcohol Swabs</td><td></td><td></td><td></td></tr><tr><td>EMG Electrodes</td><td></td><td></td><td></td></tr><tr><td>EMG Measuring Equipment/Software</td><td></td><td></td><td></td></tr><tr><td>Ear Plugs</td><td></td><td></td><td></td></tr><tr><td>Marker or Grease Pen</td><td></td><td></td><td></td></tr><tr><td>Any Single Pulse Capable TMS Device</td><td></td><td></td><td></td></tr><tr><td>Any rTMS Capable TMS Device (for TBS)</td><td></td><td></td><td></td></tr><tr><td>Any Compatible Figure-of-Eight Coil</td><td></td><td></td><td></td></tr><tr><td>Frameless Stereotactic Equipment (Optional)</td><td></td><td></td><td></td></tr></tbody></table>

tms: using the theta-burst protocol to explore mechanism of plasticity in individuals with fragile x syndrome and autism

TMS: Using the Theta-Burst Protocol to Explore Mechanism of Plasticity in Individuals with Fragile X Syndrome and Autism

Fragile X Syndrome (FXS), also known as Martin-Bell Syndrome, is a genetic abnormality found on the X chromosome.1,2 Individuals suffering from FXS display abnormalities in the expression of FMR1 - a protein required for typical, healthy neural development.3 Recent data has suggested that the loss of this protein can cause the cortex to be hyperexcitable thereby affecting overall patterns of neural plasticity.4,5
In addition, Fragile X shows a strong comorbidity with autism: in fact, 30% of children with FXS are diagnosed with autism, and 2 - 5% of autistic children suffer from FXS.6
Transcranial Magnetic Stimulation (a non-invasive neurostimulatory and neuromodulatory technique that can transiently or lastingly modulate cortical excitability via the application of localized magnetic field pulses 7,8) represents a unique method of exploring plasticity and the manifestations of FXS within affected individuals. More specifically, Theta-Burst Stimulation (TBS), a specific stimulatory protocol shown to modulate cortical plasticity for a duration up to 30 minutes after stimulation cessation in healthy populations, has already proven an efficacious tool in the exploration of abnormal plasticity.9,10 
Recent studies have shown the effects of TBS last considerably longer in individuals on the autistic spectrum - up to 90 minutes.11 This extended effect-duration suggests an underlying abnormality in the brain's natural plasticity state in autistic individuals - similar to the hyperexcitability induced by Fragile X Syndrome.
In this experiment, utilizing single-pulse motor-evoked potentials (MEPs) as our benchmark, we will explore the effects of both intermittent and continuous TBS on cortical plasticity in individuals suffering from FXS and individuals on the Autistic Spectrum.

In this article, we examine the effects of Theta-Burst TMS stimulation on cortical plasticity in individuals suffering from Fragile X syndrome and individuals on the autistic spectrum.

Fragile X Syndrome (FXS), also known as Martin-Bell Syndrome, is a genetic abnormality found on the X chromosome.1,2 Individuals suffering from FXS ...

The overall goal of this procedure is to explore cortical motor plasticity and how it relates to typical and atypical neural development using non-invasive transcranial magnetic stimulation. This is accomplished by first locating the subject's M1 motor hotspot for the first dorsal interros muscle and determining both resting and active motor threshold. The second step of the procedure is to obtain baseline corticospinal excitability.The third step of the procedure is to apply theta burst stimulation. The final step of the procedure is to evaluate resultant corticospinal excitability. Ultimately, results can be obtained that show differences in the effects of theta birth stimulation on corticospinal excitability in subjects with neurodevelopmental disorders, through the variation between baseline and post stimulation excitability.Today, we will demonstrate a type of transcranial magnetic stimulation called theta birth stimulation. This method can help answer key questions in the field of clinical cognitive neuroscience, such as how mechanisms of plasticity contribute to the pathological, neurological and behavioral phenotypes characteristic of specific developmental disorders. Before beginning this protocol, access the subject's MRI image using your frameless stereotype setup Set up.This anatomical model will be used to mark specific cranial locations and ensure the same location is stimulated each time Before beginning the theta burst stimulation, it is first necessary to determine the location of the subject's primary motor cortex. To begin seat the subject in a comfortable chair adjacent to the TMS equipment. Be sure to screen the subject to assure that there are no counter indications to TMS and explain the details of the protocol.Also, register the subject's location using the stereotactic equipment and introduce him or her to the TMS setup. Discharge a few pulses so that he or she is familiar with the clicking noise and tapping sensation. Next, set the subject up for the experiment by first asking them to present his or her right hand so that surface electrodes can be applied to the dorsal interros muscle.Before applying the electrodes, be sure to clean the skin to ensure proper registration. If the dorsal interros muscle is difficult to locate, ask the subject to make a pinching motion or to move his or her index finger back and forth. As this should make the muscle easier to find.Apply EMG surface electrodes over the first dorsal inters muscle of the right hand so that the muscle twitches caused by TMS can be recorded. Also, place a ground electrode on the meaty portion of the subject's forearm. Check your recording equipment to assure that all the surface electrodes are providing a good signal without too much noise.Both the subject and the technician should insert earplugs at this point for hearing protection. Now we are ready to determine the location of the subject's left motor cortex hand area. Although this area differs slightly for everyone, it'll generally be around 3.5 centimeters.Rost lateral of the cranial vertex with stimulation intensity set to 50%Explore a small grid around this region until a motor hotspot is located by moving the coil in small increments while watching. For the maximal MEP. Also adjust the stimulation, intensity, and angle of stimulation as needed.Once M1 has been identified, be sure to mark its location using the stereotactic equipment if available. If not, a non-toxic grease pen can be used to temporarily mark the subject's scalp. The next step in this protocol is to determine the subject's resting motor threshold.Readjust the system back to 50%power if needed, and begin single pulse stimulation to the same location while measuring the resultant motor evoked potentials. Adjust the power up or down until an MEP of greater than 50 microvolts is produced in exactly five out of 10 consecutive pulses. Record this power level as the subject's resting motor threshold.Next, ask the subject to gently pinch his or her right fore finger and thumb together using about 20%pressure while the subject holds. This pinching position begins single pulse stimulation at 50%power over the same M1 location. Measure and record the resultant meps.Now adjust the power up or down until an MEP of greater than 200. Microvolts is produced on exactly five out of 10 consecutive pulses. This power level is the subject's active motor threshold.Finally, determine a subject's baseline, MEP by stimulating the motor hotspot at 120%resting motor threshold with 10 single pulses measuring the MEP. After each pulse average the MEP values from three batches of 10 pulses. Now that the subject's threshold levels have been determined, the system can be set up for stimulation.We will be utilizing standard theta burst parameters being three pulses at 50 hertz at an intensity of 80%active motor threshold for 200 millisecond intervals to administer intermittent TBS, which has been shown to facilitate cortical activity. Generate a two second stimulation, train at the aforementioned parameters, followed by eight seconds of no stimulation. Repeat for 190 seconds, which is a total of 600 pulses to administer continuous theta burst, which has been shown to inhibit cortical activity.Generate an uninterrupted stimulation train at the aforementioned parameters for 47 seconds, which also amounts to a total of 600 pulses. Assure that the subject is comfortable and ready to begin as the rest of the protocol should be completed without interruption. Ask him or her to remain still and relaxed.Place the coil over the earlier established M1 motor hotspot and administer either ITBS or CTBS. Here we are administering CTBS. Be sure the coil remains in the correct position throughout stimulation.Following theta. Birth stimulation, immediately begin to determine post stimulus motor revoked potentials so that the transient effects of TMS can be assessed. To do this.First, set the TMS machine to deliver single pulses at 120%resting motor threshold. Now again, place the coil over the subject, same motor hotspot, assure that the coil is in the exact same location that was stimulated with TBS. Stimulate with 10 single pulses using the same electrode setup used during the previous step to measure and record the resulting batch of 10 MEP levels.These ME Ps should then be averaged and recorded as the result at this time point. Next, use the parameters to stimulate at 11 time points post TBS five minutes, 10 minutes, 20, 30, 40, 50, 60, 75, 91 0 5, and finally 120 minutes post stimulation, measure and collect new 10 pulse batch recordings and averages at each time point. Once completed, remove the surface electrodes and allow the subject to remove the earplugs and stand up.Be sure to thank him or her for participating in the experiments. Also, ask the subject to return for a future TMS session so that other TBS parameters can be investigated. The results of the TMS session will depend on the TBS pattern used.Here we see some representative results from a group when utilizing an intermittent theta birth stimulation pattern. One should notice an increase in MEP values for duration reflecting the subject's natural state of plasticity as seen here. Likewise, when utilizing a continuous the of birth stimulation pattern, one should notice a decrease in MEP values for duration, reflecting the subject's natural state of plasticity Following this procedure.Other procedures such as behavioral tasks, pharmaceutical interventions, and or additional stimulation paradigms can be performed in order to answer additional questions such as how does abnormal plasticity manifest and how can it be treated?

tms-using-theta-burst-protocol-to-explore-mechanism-plasticity

Research

JoVE Journal

Neuroscience

Neuroimaging techniques, such as functional MRI and Diffusion Tensor Imaging have become increasingly useful in characterizing the cognitive and neural deficits in autism. An examination of brain connectivity in autism at a network level along with adaptations for scanning children with developmental disabilities is presented.

Probing the Brain in Autism Using fMRI and Diffusion Tensor Imaging

We describe an experimental procedure to quantify excitability and inhibition of primary motor cortex during a motor response inhibition task by using Transcranial Magnetic Stimulation throughout the course of a Stop Signal Task.

Online Transcranial Magnetic Stimulation Protocol for Measuring Cortical Physiology Associated with Response Inhibition

Threats reliably evoke shifts in high-level ideological investment, but little work to date has explored the neural mechanisms underlying these dynamics. This paper describes how continuous theta burst transcranial magnetic stimulation may be employed to test the contribution of the posterior medial frontal cortex (and/or other regions) to threat-related ideological shifts.

Continuous Theta Burst Stimulation of the Posterior Medial Frontal Cortex to Experimentally Reduce Ideological Threat Responses

An accurate and robust polymerase chain reaction-based assay for quantifying cytosine-guanine-guanine trinucleotide repeats in the Fragile X mental retardation-1 gene facilitates molecular diagnosis and screening of Fragile X syndrome and Fragile X-related disorders with shorter turn-around time and investment in equipment.

A Robust Polymerase Chain Reaction-based Assay for Quantifying Cytosine-guanine-guanine Trinucleotide Repeats in Fragile X Mental Retardation-1 Gene

The present protocol describes the application of repetitive transcranial magnetic stimulation (rTMS), where a subregion of the dorsolateral prefrontal cortex (DLPFC) with the strongest functional anticorrelation with the subgenual anterior cingulate cortex (sgACC) was located as the stimulation target under the assistance of a fMRI-based neuronavigation system.

Individualized rTMS Treatment for Depression using an fMRI-Based Targeting Method

Here, we describe the procedure for a pilot study to explore the effect of repetitive transcranial magnetic stimulation with different frequencies (1 Hz/20 Hz/40 Hz) on Aβ and tau metabolism in rhesus monkey cerebrospinal fluid.

A Pilot Study on the Repetitive Transcranial Magnetic Stimulation of A&#946; and Tau Levels in Rhesus Monkey Cerebrospinal Fluid

Using in ovo electroporation, we devised a method to selectively transfect the auditory inner ear and cochlear nucleus in chicken embryos to achieve a cell-group-specific knockdown of fragile X mental retardation protein during discrete periods of circuit assembly.

Dissecting Cell-Autonomous Function of Fragile X Mental Retardation Protein in an Auditory Circuit by In Ovo Electroporation

Here we describe a protocol that facilitates the differentiation of human induced pluripotent stem cells into functional forebrain-specific astrocytes. This enables investigations into the role of glial cells in the pathogenesis of neurodevelopmental disorders, such as Fragile X Syndrome, and modeling of other brain disorders.

Generation and Characterization of Human Induced Pluripotent Stem Cell-derived Astrocytes Lacking Fragile X Messenger Ribonucleoprotein

Here, we present a protocol outlining the methodology to assess primary motor cortex excitability and excitability modulation using transcranial magnetic stimulation (TMS) paired with electromyography (EMG).

Assessing Primary Motor Cortex Excitability and Excitability Modulation by Pairing Transcranial Magnetic Stimulation with Electromyography

Dynamic clamp electrophysiology can establish causal links between neuronal firing deficits and ion channel dysfunction. We describe dynamic clamp methods and protocols in mouse cerebellar Purkinje neurons, noting useful resources and technical considerations. In a representative study, we add modeled sodium conductance to Tsc1-/- Purkinje neurons to rescue repetitive firing.

Dynamic Clamp Methods to Investigate Impaired Neuronal Excitability Associated with Autism

This paper describes the standardized induction of Long-term Potentiation-like cortical plasticity using repetitive stimulation protocols, followed by applying single-pulse transcranial magnetic stimulation guided by a neuronavigation system to evaluate synaptic plasticity.

Standardized Induction and Assessment of Long-term Potentiation-like Cortical Plasticity Using Transcranial Magnetic Stimulation

Explore theta-burst TMS to study cortical motor plasticity in Fragile X Syndrome and autism. This protocol measures motor-evoked potentials to reveal neurophysiological differences in neurodevelopmental disorders.

TMS: Using the Theta-Burst Protocol to Explore Mechanism of Plasticity in Individuals with Fragile X Syndrome and Autism

Explore More Videos